Michael Darcy, the executive director of the New Jersey League of Municipalities, said creating this kind of registry may help police get a better idea if is there is suspicious activity going on.

He said it's a "more centralized" way of putting up a "no solicitation" sign outside your door.

He noted with all of the telemarketing calls we’re getting on our cell phones and land lines these days, the do not knock registry may be growing because of people just want to have some privacy.

“People want to simply be left to enjoy their homes; they don’t want to be disturbed and answer the door and deal with what is probably a well-trained motivated salesperson,” he said.

He pointed out with caller ID, if someone calls and you don’t recognize the number you have the option to just ignore the call. But that’s not the case if your doorbell rings.

“They don’t know why that person is at their door. There’s kind of a more immediacy to that, so people would be more inclined to answer their door," he said.

If you sign up for the do not knock registry in your town but someone does come to your front door trying to sell you something, some towns have established monetary fines, although it’s not clear how such an ordinance would be enforced.

Religious and political groups are often exempt from these laws because of First Amendment protections.